Pollenia griseotomentosa Calliphoridae Cluster fly
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CJAI #19 – Cluster flies of North America

Pollenia rudis Face

Pollenia rudis

By Adam Jewiss-Gaines,  a research assistant at Brock University.

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When people ask me what the heck a calliphorid is (often after I have mentioned the family name and am being gawked at as if I’m crazy), I usually remark “You know those shiny flies you often see flying around in the spring and summer?”  This isn’t technically 100% accurate since the genus Pollenia, one of the most commonly encountered genera of the family, is in fact non-reflective and grey.  Upon closer inspection, a keen eye can also observe varying amounts of wrinkled, yellow hairs on the thorax.  These two qualities distinguish Pollenia from other blow flies throughout North America.  Despite being a little dull when compared to their more eye-catching iridescent relatives, Pollenia are ecologically important insects as they aid in plant pollination and the processing of various biomaterials.

Pollenia often become particularly active during the spring and summer months once the temperature warms up, although they can occasionally be spotted indoors in the wintertime on a warmer day.  With a sudden onslaught of large, grey insects flying around when the snow begins to melt, it comes as no surprise that people tend to get irritated with them and consider them pests.  Oftentimes they are mistaken as houseflies (Family Muscidae) causing Pollenia species to be labeled as potential food contaminators, but this is not the case.  These insects are also particularly well-known for their clustering behaviour on walls, earning them their common name: cluster flies.

Even though Pollenia are extremely common, their general biology is largely unknown with a few exceptional details. It is known that larval Pollenia are parasites on various other organisms, such as maggots and worms. For example, Rognes (1991) noted that Pollenia pediculata, one of the most common species found throughout the continent, is a parasite of the earthworm species Eisenia rosea. Aside from this little tidbit however, specific information regarding the life cycles of Pollenia species is relatively scarce and further studies in this particular field would greatly improve our knowledge of the genus.

Pollenia griseotomentosa Calliphoridae Cluster fly

Pollenia griseotomentosa

Until very recently it has been thought that all Pollenia found in North America were the same species (Pollenia rudis), but after examining various collections throughout the world, Knut Rognes found that six members of the genus occur throughout the region.  Terry Whitworth adapted much of Rognes’ work shortly thereafter into a nice, clean, simple identification key for North America. With accurate images and photography, however, characters could be even easier to distinguish and observe when one is able to compare a photograph to the creature they have under their microscope.

Therefore, to further expand on Terry’s key and clarify important visual characters, I collaborated with him and Dr. Steve Marshall to create a fully-illustrated digital key for distinguishing the six North American Pollenia species from one another.  Now published in the Canadian Journal of Arthropod Identification, Cluster Flies of North America couples high-resolution images of important traits with a clean and simple interface to create a handy tool to be used by entomologists and non-entomologists alike. If you are relying on this key for identification, it is recommended to use physical specimens of Pollenia rather than images or photos, since even the best of hand-photographs have difficulty capturing key features. In addition, distribution maps are provided for each species, constructed from locality data of specimens from the University of Guelph Insect Collection and Terry Whitworth’s personal collection of Pollenia.

Creating this key has been a great opportunity, and I hope the entomological community is able to make good use of it. My sincere thanks go out to Steve Marshall, Terry Whitworth, the editors, and my labmates and friends for all of their support.

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Jewiss-Gaines, A., Marshall, S.A. & Whitworth, T.L. (2012). Cluster flies (Calliphoridae: Polleniinae: Pollenia) of North America, Canadian Journal of Arthropod Identification, 19 DOI: 10.3752/cjai.2012.19

Rognes, K. 1991. Blowflies (Diptera, Calliphoridae) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica Vol. 24.

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Respect your specimens

By Crystal Ernst, PhD Candidate (McGill University)

Since I finally submitted my manuscript to a journal (YAY!), I’ve been tying up the little loose ends remaining at the end of the project. You know: organizing the useful data and image files, tossing the files marked “MESSING_AROUND_WITH_DATA_v.29), tidying up my R code, and, perhaps most importantly, curating my specimens.

I’m not going to go into too much detail about the project here (I’m saving that for another post). I will say, though, that the work I just completed includes just over 2,600 beetles from a single location in Nunavut (Kugluktuk, where I spent my entire first field season).

Two major aspects of the physical work (as opposed to the thinking, reading and writing) involved in an ecological/entomological project such as this one are the pinning and the identifications. Some of the tasks are a bit tedious (cutting labels; entering data; gluing over 800 specimens of the same tiny, plain black ground beetle to paper points), and some of them are thrilling (finally getting over the “hump” of the morphological learning curve and feeling good and confident when working with your keys; having experts tell you “Yep, you got those all right”; discovering rare species or new regional species records). In the end, in addition to the published (*knocks on wood*) paper, you have boxes or drawers full of specimens.

The specimens are gold. (Read this post by Dr. Terry Wheeler to understand why.)

Unfortunately, they don’t always get treated as such.

In the two-ish years that I’ve been working in my lab, we’ve had two major “lab clean-up days”. The first managed to get rid of a lot of clutter (old papers, broken apparatus, random crap). The second involved going through the “stuff” that was eating up all the most valuable storage space: specimens. Years and years worth of graduate and undergraduate projects’ specimens, stashed in freezers, boxes, bags and vials of all shapes and sizes.

Some things were in good shape (pinned well, or in clear ethanol). Other things were, well, downright nasty: gooey beetles in sludgy brown ethanol, dried up bits of moth wings in plastic containers, and a little bit of “what in the name of pearl is growing on that agar plate???” in the fridge.

None of these items were kept – their value as useful specimens was nil. So, the physical representation of some student’s work – probably months or years worth of work – was tossed in the trash.

Others, happily, were tucked back into drawers and cupboards, because someone had taken the time to ensure the specimens were well-preserved.

However, even many of these were suffering from a serious issue: bad labels.

Allow me to illustrate the point. This is a bad label:

This is also a bad label:

The first, you’ll note, is written in ballpoint pen (which fades) on a torn piece of notebook paper and contains almost no information. The second, although it looks fancier and perhaps more sciencey, is just as bad: it contains a cryptic code that is useful only to the bearer of the lab notebook in which said code has been written down. Or, perhaps the code is completely intelligible to the researcher who developed it, but the key to it exists only in his or her head.

To everyone else, it is meaningless. Neither of these labels indicate who collected the specimen, where, when, or how. And we all know what happens in labs: upon completion of their degrees, students move on, email addresses change, notebooks are misplaced, data files are not backed up. The labels’ codes can never be broken, and the scientific value of the specimens – *poof*.

While there’s nothing wrong, in theory, with using labels like these temporarily (although there is always a risk that they will be misinterpreted or misunderstood after a little while, even by the person who wrote them), they are absolutely useless as permanent records.

These are good labels:

These labels, properly affixed to a specimen, provide clear and universally understood information. One provides the location, including GPS coordinates, a method of collection, a date, the name of the collector(s). The information that goes on this label can vary a bit (it may include information about the habitat or host plant, for example), but those are the basic requirements. The smaller label is typically affixed on the pin below the first, and contains the specimen’s scientific name and the name of the person who identified it (it is the “det. label”, i.e., “determined by”). These labels, and therefore the specimen with which they are associated, will remain useful for decades, even centuries.

I am totally guilty of both of the offenses I just explained (the gooky vials of nastiness and the bad labels). For my undergraduate honors project, I identified close to 8000 spiders, mites and insects to the Family level – it was hundreds of hours of microscope work. Then I stuffed all those specimens back into vials with cryptic little codes, like V-1-F(!), hand-written on STICKERS(!), which I placed on the LIDS(!) and not even in the vials themselves(!). Oh, and I’ve long since lost the notebook that contained my decoder key(!). THIS IS ALL SO BAD. I have no doubt that those boxes of vials, which I once prized so highly and felt such pride for, have been unceremoniously tossed in the trash by my former advisor.

Well, I’ve learned from my mistakes, and from working with museum and other collection specimens. I now understand that each specimen is deserving of respect – it’s the original data after all – and that means it should be properly preserved, and labelled.

So.

Last week I spent a great deal of time, as I said, tying up my loose ends. The last thing I needed to do was remove my cryptic labels (the second in the series up there is an actual example of one of my own “secret code” labels) and replace them with proper ones, sorting and tidying up the collection in the process. The end result?

This:

Frankly, it’s a thing of beauty. It’s also enormously scientifically valuable. These specimens will be deposited in various nationally-important collections and museums, like the CNC.

As a matter of fact, just last week I was at the CNC, and I saw specimens bearing the name of the last person to do a comprehensive survey of the insects in Kugluktuk, back in 1955. That tiny but so-important label suddenly made me feel connected to the man who, almost 60 years earlier, had stood on the same stretch of tundra as me, holding and perhaps delighting in the very specimen that I held in my own hand.

Giving my specimens the respect they deserve is worth it, not only for the scientific value, but also because perhaps, 60 years from now, another grad student will discover my name on a specimen’s det. label. Perhaps she, too, will feel that same wondrous sense of connection to the the greater scheme of scientific discovery…

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Original post at: http://thebuggeek.com/2012/06/25/respect-your-specimens/

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Backyard moth’er

By Ian Maton,  Member of the The Alberta Lepidopterists’ Guild and the Altaleps discussion list, BugGuide editor and contributor to the Moths Photographers Group (MPG)
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Great Tiger (Arctia caja)

My two light traps

My journey into live moth trapping started a relatively short time ago towards the end of 2007.  My brother, who lives in the UK and has been live moth trapping since 1999, frequently encouraged me to buy a light trap and in August of 2007 I finally gave in and purchased a small 12V portable, 6W Heath trap at the British Birdfair while on vacation in the UK.  As this point I should explain that live moth trapping has become quite popular amongst bird watchers in the UK (my other hobby), to the extent that you can now purchase quite a lot of entomological paraphernalia at the annual Birdfair.

My backyard photographic setup

So it was, with some trepidation, that I put my light trap out for the first time in Lethbridge, Alberta, at the end of August 2007.  My camera equipment was fairly basic but I did manage a few photographs and I think it is safe to say that I was completely hooked from that point on.  I was able to identify a few of the moths but, although the situation has improved in recent years, identification guides were hard to find.  In the UK there were already a good number of handbooks to help with moth identification but this did not appear to be the case in North America.  I did buy some of the “Moths of North America North of Mexico” series and the Peterson guide “Moths of Eastern North America” but initially, my main aid to identification was BugGuide.net.  Not being able to separate the moths into their respective families meant that identifying any moth could take me several hours and sometimes involved my scanning through 300 plus pages of Noctuids on BugGuide!  This was not all bad as it forced me to become somewhat familiar with the family names and gave me a great sense of achievement when I did identify a moth.  However, in April of 2010, something happened which dramatically changed all this.

Delphinium Leaftier (Polychrysia esmeralda)

I had started to submit one or two photographs to BugGuide and one of these was Delphinium Leaftier (Polychrysia esmeralda).  While there were pinned images of this moth, there were very few live images in North America and I was contacted by Bob Patterson who asked for permission to display my photographs on the Moth Photographers Group (MPG) website.  Shortly after this it became apparent that I was photographing some moths that were not yet in BugGuide.  Bob created a couple of guide pages for me so that I could upload my photographs to the correct taxonomic spot but quickly suggested that I be given editor privileges on BugGuide.  All this was extremely exciting to me and added an entirely new dimension to my hobby.  In addition to this, Bob put me in contact with Gary Anweiler who, based in Alberta, is one of the premier experts on Noctuids in North America.  Since then Gary has been instrumental in helping me to identify moths.  Always patient and quick to respond I can’t thank Gary enough for his help and advice over the last few years.

Bilobed Looper (Megalographa biloba)

2010 was a very big year for me with regards to moth trapping.  A major highlight occurred in October of 2010 when my wife (I was then working long hours and had convinced her to help out with the moths) picked a Bilobed Looper (Megalographa biloba) out of the trap.  It was immediately identifiable and seemed to be an unusual sighting.   Indeed, Gary Anweiler confirmed that there had been only two previous records in Alberta and only two additional records for western Canada.  I can’t think of a better way to end the 2010 mothing year!

White-lined-Sphinx-(Hyles-lineata)

Since then I have continued to add photographs to BugGuide and I am pleased to say that a good number of them have been picked up and added to the MPG website.  I have also pieced together a database of the moths I’ve seen which now includes 245 species.  2011 was another landmark year when I attempted to record the number of each moth species that had been in my trap.  This had been practically impossible until I become familiar with the more common species I was getting.  Consequently, I can now say that my most common moth in 2011 was, by far, Thoughtful Apamea, followed by Glassy Cutworm, Olive Arches, Bronzed Cutworm and Bristly Cutworm.  This was a very nice personal achievement.  Most recently I have started a blog “Moths of Calgary”.  I have to admit that I got the idea from my brother who created a blog “Moths of Boughton-under-Blean”.  Apart from the enjoyment I get from posting my latest sightings, I’m hoping that it may help to advertise live moth trapping as an interesting hobby in Canada.

So far, the highlight of 2012 was my first Silkmoth seen in the Twin Butte area of Southern Alberta while on a short vacation.  Glover’s Silkmoth (Hyalophora gloveri) is a species that I’ve been trying to see for a number of years and there they were, in daylight, perched on the side of our cabin when we arrived!  Other colourful and unexpected species that I’ve seen include my first backyard Sphinx moth, a White-lined Sphinx (Hyles lineata) and a Great Tiger Moth (Arctia caja).

Glover’s Silkmoth (Hyalophora gloveri)

For me there are two things which make live moth trapping a really great hobby.  Firstly, you never know what you are going to get!  It may be a while before you see some of the more eye-catching moth species but that’s all part of the appeal.  Secondly, it’s something that you can do without venturing further than your own backyard!

While, at first, identification was a bit of a struggle, the sense of achievement gained when I did identify a new moth, for me, more than compensated for the time spent getting there.  Live moth trapping is a fascinating hobby and it is my hope that, over time, it will become a more popular, eventually contributing to the knowledge of moth movements and distribution throughout Canada.

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Stick Insect Baculum extradentatum
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Physiology Friday – Nitric oxide causes a sticky situation

Physiology Friday is a monthly column by UWO PhD candidate Katie Marshall and will feature new Canadian research on insect physiology.

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Nitric oxide (NO) is usually overshadowed in fame by its more famous cousin laughing gas, but it’s difficult to think of many simple molecules that have such a variety of important biological functions.  While NO only lasts a few seconds in the free gaseous state in the blood, it has been implicated in processes that involve everything from immune function to neurotransmission.  One important role for NO is in the cardiac system, where it functions as a vasodilator and in vertebrates it slows heart rate, while in insects it has the opposite effect.

Stick Insect Baculum extradentatum

Baculum extradentatum photo by Sara da Silva

Most of the research about the physiological functions of NO has focused on vertebrates, but recent work published in the journal of Cellular Signalling by graduate student Sara da Silva and her postdoctoral fellow mentor Rosa da Silva in the lab of Angela Lange (University of Toronto Mississauga), has shown that, unlike other insects, the Vietnamese stick insect Baculum extradentatum can respond to NO like a vertebrate.

“Our initial research interests in cardiac physiology were influenced by earlier work indicating that stick insect hearts are innervated and can be modulated by endogenous chemicals [like NO],” says study director and University of Toronto Biology professor Angela Lange.  “It is for this reason that we chose this understudied organism, which contains a simplified cardiovascular system that can be considered a model for work on other cardiac systems.”

The researchers first attempted to find the natural source of NO in the stick insect by removing hemolymph (blood) samples and staining for the presence of an enzyme that produces NO.  Then they examined the effects of NO on heart rate by dissecting the dorsal vessel out and maintaining it in a Petri dish with physiological saline.  They could measure heart rate through the placement of electrodes on either side of the dissected heart, and monitor the effects of various chemicals on the cardiac activity of the stick insect.   They also could examine whether heart rate was mediated by the central nervous system by leaving the nervous system attached or not.

insect heart rate

The effects of nitric oxide on the heart rate of B. extradentatum. Figure 3 from da Silva et al. 2012

They found that the hemocytes (blood cells) of the stick insect were producing an enzyme that was similar to the enzyme other animals use to produce NO.  In addition, the more of a chemical called MAHMA-NONOate (which produces NO) they added, the slower the stick insect hearts beat.  This surprising effect was completely opposite to what had been found in other insects and was more like the response of the vertebrate heart.

“Insects have evolved different strategies depending upon life history, and have co-opted different messenger systems for this success,” says study author da Silva. “We need to understand the full ecology of all species to finally appreciate the factors involved.”

Using the same setup, they also tested other components of a system of compounds that they thought might be involved in the pathway that produces NO that leads to decreased heart rate in B. extradentatum.  They believe that NO is produced in the hemocytes, travels to the wall of the heart, and then leads to the production of a messenger molecule that decreases heart rate.

Schematic diagram of the proposed regulation of cardiac activity in B. extradentatum by the gaseous signaling molecule, nitric oxide (NO)

Schematic diagram of the proposed regulation of cardiac activity in B. extradentatum by the gaseous signaling molecule, nitric oxide (NO). Figure 7 from da Silva et al. 2012.

“This study further emphasizes the evolutionary links between the physiological processes of vertebrate and invertebrate systems,” says da Silva. “Our findings suggest that signaling molecules (such as NO) common to both types of organisms can have similar effects on cardiac activity.  These novel findings demonstrate that the study of vertebrate systems can be complemented with studies in model invertebrate organisms.”

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da Silva, R., da Silva, S.R. & Lange, A.B. (2012). The regulation of cardiac activity by nitric oxide (NO) in the Vietnamese stick insect, Baculum extradentatum, Cellular Signalling, 24 (6) 1350. DOI: 10.1016/j.cellsig.2012.01.010

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A Meager Existence Fit for a King

By Christopher Cloutier, Naturalist, Morgan Arboretum
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The Morgan Arboretum of McGill University, with its 245 ha of forest and interspersed field habitats, is home to nearly 50 species of butterflies. Over the past two years I have tried to document all species occurring within the Arboretum and made note of the date of their earliest appearance. Many of the butterflies observed are the “expected” species, such as the Question Mark, White Admiral and the Monarch.

Others, though, were much more exciting finds: the Banded and Acadian Hairstreaks, the Baltimore Checkerspot and the Silver Spotted Skipper to name a few. Of all the highlight species found over the past two years, one that truly stands out is the Hackberry Emperor (Asterocampa celtis).

Hackberry Emperor looking down from a high perch. Credit: Christopher Cloutier

Like many other butterfly species, the Emperor is specific to one type of host plant for its larvae. You guessed it: the Hackberry Tree (Celtis occidentalis). Although the Arboretum lies within the native range for this tree, it is one that is rarely encountered. It is found naturally on the outskirts of the property and nowhere near the main walking trails; that is, until about 10 years ago when the Arboretum planted several trees near the parking lots along the main road. The trees today are no taller than 4m but are growing rapidly. This represents nearly the entire habitat in which the Emperors were discovered back in 2010, and this is the tale of their unusual discovery.

Unlike most of the species which I have documented over the years, this one came as a report from a concerned visitor to the Arboretum. I remember this case vividly as it was quite unique. A visitor to the Arboretum came by the gatehouse to mention that they were seeing a large butterfly up close. In fact, the butterfly was landing on them with regularity every time they passed by a certain location. This was something I had to see for myself. Not knowing what to expect I followed the man to where he encountered this critter and sure enough we were standing right next to the Hackberry plantation. Within less than a minute a butterfly alighted on my shoulder, a species I had never encountered before. I quickly collected it with my aerial net and brought it back to my office for a closer look.

It didn’t take long to discover that this beautiful butterfly was indeed the Hackberry Emperor. After doing a little bit of research, I realized that this was not the first time that this species had been encountered at the Arboretum, but it was the first time in nearly half a decade. I decided to have a little photo shoot with the insect just to get some record shots. I then gave it a sip of grape juice and brought it back to where I first captured it.

Hackberry Emperor refueling after a photo shoot. Credit: Christopher Cloutier

I decided to have a closer look at the Hackberry trees scattered about on the grassy lawn. There were only five trees, not more than twice my height, and I quickly noticed why the butterflies were here. They were breeding. After searching the gall-riddled leaves of the Hackberries, I discovered several clusters of eggs as well as some recently hatched first instar larvae. Again, upon my arrival several adults were patrolling the area trying to frighten me away, or maybe trying to get a closer look at who I was. It didn’t seem to matter what colour clothing I was wearing, they just seemed interested in large silhouettes near their nursery.

Eggs and freshly hatched larvae of the Hackberry Emperor. Credit: Christopher Cloutier

Since this first discovery I have encountered Hackberry Emperors every summer since. They are typically active in mid-June and their activity time extends into July and August. Their dependence on a single tree species makes this butterfly quite interesting. Had we chosen to plant a different species of tree as a windbreak for the parking area, we may not have ever encountered this butterfly again. It seems now that we have made an ideal artificial breeding habitat for this beautiful insect, and hopefully they choose to use it year after year, that is, as long as they abide by our strict “no harassing other visitors” policy.

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